Intense nano-interfacial interactivity stimulates the OER in a MOF-derived superhydrophilic CuO–NiO heterostructure

To decrease the current output of carbon emissions and resolve the twin problems of CO2 emission and fossil fuel exhaustion, it is critical that clean energy alternatives are developed. Hydrogen is a promising carbon-neutral candidate that can effectively attenuate global energy crises and provide a sustainable solution. However, large-scale hydrogen production from electrochemical water splitting is still a challenge that must proceed through the sophisticated four-electron transfer mechanism of the oxygen evolution reaction (OER) at an anode. Intensive research is currently proceeding to develop efficient, durable, earth-abundant, and inexpensive electrocatalysts for the OER. Inspired by synergistic effects arising due to the interfaces of heterostructures, we designed nanointerfaces between the CuO and NiO phases in CuO–NiO hybrid nanostructures formed over nickel foam (NF), which showed strong interactions. The catalyst was synthesized via the hydrothermal growth of a metal–organic framework (Cu-BDC) on NF, followed by temperature-controlled calcination. The contact angle measurement was 0°, which demonstrates the superhydrophilic nature of the catalyst. The CuO–NiO/NF catalyst exhibits a low overpotential of 231 mV in driving a current density of 10 mA cm−2 and a Tafel slope value of 100 mV dec−1. The catalyst durability was measured for up to 20 h using chronoamperometry. Density functional theory (DFT) calculations indicate the existence of strong interfacial interactions, which were confirmed via X-ray photoelectron spectroscopy analysis, and the results obtained from DFT are also in accordance with the experimental data.